1. Field of the Invention
The present invention relates to recording media, and more particularly, to an apparatus and method for searching for defective addresses of recording media.
2. Description of the Related Art
With a recent trend to high-capacity recording media, many efforts have been made to utilize a structure in which defective recording locations are replaced by other recording locations. The recording medium is comprised of sectors which store and record data on their surfaces, and defects of the sectors are tested while manufacturing the recording medium.
Defective sectors cannot store data. The list for defective sectors is called a "primary defect list" (hereinafter called PDL). The PDL is stored at a predetermined location on a disk.
The recording medium is provided with additional sectors to replace the defective sectors. Defects of these extra sectors are called "secondary defects", and extra sectors with such defects are classified in a "secondary defect list" (hereinafter called SDL).
When a driver having recording media is powered up, the PDL and SDL are read out and stored in a random access memory (RAM). A controller such as a microprocessor prevents data from being recorded on the defective sectors, using information on the PDL and SDL.
A recording medium such as a digital versatile disc (DVD) RAM, which repeatedly records and reproduces, first searches the defect list before recording or reproducing data. However, the defect list is very large, typically on the order of about 64 Kbytes. Accordingly, it takes much time to search the entire defect list and recover from defects.